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Hitachi Ex120 Problem

Mohd Azizi

Member
Joined
Dec 16, 2020
Messages
5
Location
Rompin, Malaysia
originally this machine works well even though all the wires related to the working mode have been cut,,,and I have changed all the strainers and my plan is to make a pressure tester,,,may I know what the pressure reading is?
 

gilcaay79

Member
Joined
Oct 10, 2023
Messages
5
Location
Oroqueta city Philippines
You need the manual to replace the sensor and set the voltage properly. You can put the machine into a limp mode in order to get it home. If you look on the bottom of bothe pumps there is a four bolt cap plate over the end of the swash cylinder pistons. If you remove that plate you will see that it has a peg sticking up from the underside of the plate, if you turn the plate 90 degrees and replace it back in the hole then the pin will put the pumps into about halve swash and they will stay there the you can get the machine home if you feather the controls. As for your problem it sounds to me like the pump displacement solenoids, they tend to work fine when cold but as the machine heats up the coils break down and they quit working then the machine goes to full swash and stalls. Good luck.
Hello 3Doc do you have a service manual of ex120-3
 

4020farmer

New Member
Joined
Oct 7, 2024
Messages
4
Location
Kentucky
I did the same conversion directions suck and no help. So I printed out all the pictures I could find showing hose routing and pump adapter. Ok got that, then could not find where hose went on valve block. I compared pictures of all the different kits for sale and found one part I didn't have and couldn't buy separately. It is an adaptor to replace DP sensor which is where hose goes. I took an old DP sensor I had took It apart, drilled It out brazed in a hose fitting sealed up the holes on the sides re installed Orings and it worked.
All functions work fast enough, Your not going to get the speed of a new machine but its workable.

Send me your email and ill send pics of what I followed. I don't know how to post pics.
Kevin
By chance do you still have pics of where you did this? I am in the process of converting a 120-2 and it’s giving me the run around. Thanks
 

Lexa

New Member
Joined
Jul 26, 2025
Messages
2
Location
St. Helena island
yes it is already toasted, its at my friend now so he tries to get it work again. i ordered few transistors from china, when we get them then i can start finding what has caused the problem. i think it is the angle sensor. and its possible that someone has replaced sometime the 1a fuse with bigger one, so the box has given the holy smoke. there was one transistor down, and the place named r1 component toasted so badly i had to find another box where i could spy what component it was. but its ok now, just waiting the components arrival from china.
Hi, have you managed to fix your PVC controller? I have several boxes, once damaged, the big 10 Ohm resistor heats up till it burns. Any idea what components do get always damaged? I have desoldered a couple of transistors, but were all good...
 
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